In manufacturing environments, work places in most cases include specifically designated work areas which are each bounded by a protective fence or the like for placing therein a work machine such as a large robot for welding, picking or other work and a machining center that could be a source of danger.
In such a work place, it has been conventionally practiced to use a worker safety management system for establishing an interlocking relationship between the entry/exit of a worker into and out of the designated work area, identified by the use of a mechanical key or a card key, and the operation of the work machine within the designated work area, with the aim of preventing the worker from encountering any danger within the work area. See Patent Document #1 and #2.
For such a worker safety management system to be able to ensure the safety of the worker and improve and maintain the work efficiency, it is essential that information is closely exchanged between the work machine and the worker.
[Patent Document #1]
Japanese patent laid open (kokai) publication No. 2001-160534
[Patent Document #2]
Japanese patent laid open (kokai) publication No. 2001-270700